1. Field of the Invention
The present invention relates to the fields of molecular biology, virology and immunology. More specifically, the present invention provides an attenuated recombinant chimeric sindbis-western equine encephalitis virus (WEEV) and discloses its use as vaccines and in serological and diagnostic assays.
2. Description of the Related Art
Western equine encephalitis virus (WEEV) is not as neuroinvasive as Eastern equine encephalitis virus (EEEV). However, its transmission and pathogenesis are similar. Mosquitoes carry the virus from the wild bird reservoir to the dead-end hosts, horses and humans. Female mosquitoes acquire the virus by taking a blood meal from an infected host. The virus infects the epithelial cells of the midgut of the mosquito and spreads through the circulation to the salivary glands where it sets up a persistent infection. The virus enters a new host when the mosquito regurgitates virus-containing saliva into the victim's bloodstream. The virus replicates in the capillary endothelial cells, macrophages, monocytes, liver, spleen or lymphatic tissue.
Systemic symptoms (chills, fever, myaglia) occur at this time, perhaps due to production of interferon. A secondary viremia follows the replication in the reticuloendothelial system and allows infection of the target cells in the brain. Damage is due both to cell death following infection and to inflammation. The disease occurs only in months when mosquitoes are active. Subclinical infections greatly exceed the number of clinical cases. Although many infections do not progress beyond the systemic phase, infection of the brain (signaled by severe headache and nausea) is followed by a rapidly progressive downhill course. Although a vaccine has been developed for horses, this vaccine is not useful for the general population. Hence, it is necessary to develop vaccines that can be used for the general population since infants are particularly susceptible to CNS disease caused by this virus and survivors may have severe CNS sequelae.
Thus, prior art is deficient in vaccines that can be used to treat and/or prevent an individual from infection caused by western equine encephalitis virus. The present invention fulfills this long-standing need and desire in the art.